Apparatus for the extraction of helium from gaseous mixtures



Oct. 4, 1932- R. R. BOTTOMS 6 APPARATUS FOR THE. EXTRACTION OF HELIUM F ROM GASEOUS MIXTURES Filed June 25. 1931 4 Sheets-Sheet 1 iNVENTOR ATTORNEYS Oct. 4, 1 932. R, BQTTQMS 1,881,116

APPARATUS FOR THE EXTRACTION OF HELIUM FROM GASEOUS MIXTURES Filed June 23. 1931 4 Sheets-Sheet 2 INVENTOR ATTORNEYS cum 06E. 4, 1932. A R, R son-0 5 1,881,116

APPARATUS FOR THE EXTRACTION 0F HELIUM FROM GASEOUS MIXTURES Filed June 23. 1931 4 Sheets-Sheet 4 INVENTOR lfoberfjfqgerflofiams BY AQW PMM 7 A ATTORNEYS e-IOI Patented Oct. 4, 1932 UNITED STATES PATENT OFFICE ROBERT ROGER BOTTOMS, OE LOUISVILLE, KENTUCKY, ASSIGNOR TO THE HELIUM COMPANY, OF LOUISVILLE, KENTUCKY, A CORPORATION OF KENTUCKY APPARATUS FOR THE EXTRACTION OF HELIUM FROM. GASEOUS MIXTURES application filed June 23,

This application is a continuation in part of my prior copending applications Serial Nos. 309,009, filed Sept. 28, 1928, (now Patent 1,821,540, granted September 1, 1931),

382,221, filed July 30, 1929, and 452,020, filed May 13, 1930, in which applications are claimed various novel features of the process carried out in the apparatus forming the subject matter of the present application.

The present invention involves certain improvements over the apparatus disclosed in my prior Patent 1,569,943, issued Jan. 19, 1926. 4

The main object of my present invention is to provide certain improvements in the apparatus whereby substantially all of the helium may be obtained and of a higher degree of purity. 7

By means of my apparatus the gases, other than helium, in the gaseous mixture are caused to liquefy under'a high pressure in a condenser. If there be a comparatively small amount of helium present in the mixture, substantially all of it will be dissolved in the liquid under high pressure and thus substan-' tially the entire gaseous mixture will be liquefied. If there be a larger amount of helium, a considerable portion of it will be in solution in the liquid. The liquid is delivered past a throttle valve to a liquid collecting pot or chamber under lower pressure where the dissolved helium is released and the residual liquid is then delivered past a second throttle valve to a still lower pressure where it evaporates to cool the condenser.

In commercial practice it is customary after extracting the helium to store it in-steel cylinders under comparatively high pressure, for. instance, 2000 pounds per square inch.

One object of my invention is toeffect the separation and removal of the helium in asubstantially pure state and as a single step as distinguished from previous apparatus in which extraction, rectification, recompression or other such series of steps are employed.

1931. Serial No. 546,244.

' A further object is to efl'ect the separation and storage of the helium by a single compression, the impurities being liquefied out at this pressure so that the separated residual helium still under substantially this initial pressure is delivered from the apparatus for storage.

As an important feature of my present invention the apparatus is provided with means whereby the gas escaping. from the liquid in the collecting pot and containing substantially all of the helium is recompressed and the non-helium constituents are reliquefied, the reliquefaction being accomplished by the liquid withdrawn from the liquid collecting pot in the main separating cycle. Thus the liquid from the pot of the liquefying cycle serves not only to cool and liquefy the raw gas, but also serves to cool and liquefy the recompressed helium containing constituent which has been taken off in gaseous form from the collecting pot. The helium separated from the liquid in the purifying cycle includes substantially all of the helium of the raw gas and has by far greater purity than that produced by the apparatus shown in my Patent 1,569,943 above referred to.

The gases with which helium is most commonly found have boiling points at atmospheric pressure above the critical temperature of the helium. The present invention is applicable to the separation of other gases. such as neon, where the same relationship of critical temperature to the boiling point of the other constituents exists. Therefore for the purpose of this invention, neon is to be considered as the equivalent of helium.

Other objects, advantages and important features of my invention will be pointed out hereinafter or will be apparent from a consideration of the following description and the accompanying drawings showing certain embodiments of the apparatus.

In these drawings:

Figs. 1 to '4 inclusive are somewhat diagrammatic views, partly in elevation and partly in section, showing four difierent forms of apparatus embodying my invenih san example of the gas which may be treated by the apparatus shown in Fig. 1, I may mention a natural gas which, after the removal of all carbon dioxide and water vapor, has the following composition:

Per cent Helium; Methane Ethane 2 Nitrogen. a 76 Any other helium containing gas free of carbon dioxide and water vapor may be used. r

In the form illustrated in Fig. 1, the natural gas in which the helium forms a rela tively small proportionate part, is delivered ;hrough a pipe 10 to a multi-stage compressor 11 where it is compressed to approximately the pressure required for both separation and storage. This may be approximately 2000 pounds gauge pressure. The compressed gas is delivered through a pipe 12 and a suitable cooler 13 where the heat of compression is removed. The gas is then delivered through a pipe 14 into a heat interchanger 15, thence through a pipe 16 to a coil 17 in a chamber 18 of a condenser 19 to a collecting pot or receiver 20 in the lower part of the condenser. 1

.The pot or collecting receiver 20 is' connected to a crude helium separating receiver 21 by a pipe 22 having a throttle valve 23. The upper part of the receiver 21 is connected by a pipe 24 to a pipe 25 leading through the 'interchanger to a pipe 26 leading tothe compressor 11. This pipe 26 is provided with a valve 27, and if the supply pipe 10 and the pipe 26 are delivering gas at the same pressure they may enter the same stage of the compressor, or the gas delivered through the pipe 26 if at a higher pressure than the gas delivered through the pipe 10 may go to an intermediate stage or may act on the supply of natural gas through an injector 28.

The lower part of the receiver 21 is connected by a pipe 29 to the lower part of the condenser 19 and said pipe is provided with a throttle valve 30. The upper part of the condenser 19 is connected toone end of the heat interchanger 15 by a pipe 31, and the opposite end of the heat interchanger may have an outlet pipe 32 for deliveringthe non-helium containing constituents of the gas.

The pot 20 is provided with a pipe 33 leading through the upper part of the condenser chamber 18 and the heat interchanger 15 to a manifold 34 which may be provided with a control valve 35 and with connections to the cylinders or other containers 36 for the helium under pressure.

The operation of this apparatusis substantially as follows:

The valves 23, and are closed at the start ofoperation and the pressure is built up to approximately 2000 pounds in advance of the valve 23. This valve is then opened and the gas is allowed to escape in sufiicient quantity to maintain. the pressure within the pipes 12 and 14, coil 17' and chamber 20 at the ap roximate value of 2000 pounds. In

throttlmg the gas from the high pressure through the valve 23, it undergoes adrop in temperature by the well known J oule- Thompson efl'ect. From the receiver 21 the cold gases pass through the valve 30, pipe 29, chamber 18 of the condenser 19, pipe 31 and passage 37 of the heat interchanger 15 to the atmosphere, or when it is desired to save the gas, into a pipe line through the ipe 32. The gases which have been cooled y-the Joule Thompson efiect in throttling through the valve 23, take up heat from the ingoing gasesin the pipe 14, and cool these gases to a lower temperature.

Subsequently the gases flowing through the pipe 16, coil 17 and chamber 20 and reaching the valve 23 have already been cooled to a low temperature, and thus undergo a further drop in temperature at the valve 23 until a point is finally reached where the gases other than helium reach the liquefaction point. This point for nitrogen is approximately 195 C.

During this preliminary cooling period the valve 35 remains closed, preventing the delivery of gases to the manifold 34. When this point is reached, gases will be liquefied in the coil 17 and chamber 20. If the gas does not contain more than a small proportion of helium, for instance about 2%, the helium itself will be dissolved in the liquid at the pressure and temperature existing in the apparatus. When this liquid is throttled through the valve 23 into the chamber 21, most of the helium in solution will be given ofi in the'chamber due to the reduction in pressure. The pressure of the liquid in the receiver 21 will be maintained at the proper operating point by manipulation of the valves 27 and 30. This pressure in the receiver 21 should be such that a comparatively small amount of-the liquid will he evaporated in the chamber 21, but substantially all of the helium together with some of the liquefied gases will separate from the residual 1i uid. This operating pressure is preferably etween and 200 pounds for a gas of the character above referred to.

At the valve 30 the pressure may drop to substantially that of the atmosphere, and

the liquid from the bottom of the receiver 21 into the condenser-18 where it serves to effect substantial] complete liquefaction of all of the non-he ium containing constituents of the gas delivered through the coil 17 and into the chamber or pot 20. The valve 27 in the pipe 26 also serves to maintain the desired pressure in the chamber 21 and the delivery back to the compressor of the crude helium separating in the chamber 21.

If the percentage of helium inthe gas to be treated is such that all of the helium dissolves in the liquid in the chamber 20, all

of the helium will likewise pass into the chamber 21, and the crude helium, that is the helium separating from solution, together with gas resulting from evaporation of liquid in the chamber 21, will pass to the compressor. This crude helium in returning to the compressor passes through the pipes 24 and 25, and'in the pipe 25 gives up its heat to the incoming gases delivered through the pipe 14. The crude helium in entering the compressor becomes mixed with a further supply of the incoming natural gas and in this way the amount of helium in the gas being compressed by the compressor 11 will greatly increase in value until the point is reached where the gas entering the coil 17 contains an amount of helium in excess of the saturation point for the li uefied gases. When this point is reache namely approximately 3% helium, the helium in excess of about 3% will not be dissolved in theliquid in the chamber 20, and as it will not be liquefied at the temperature existing in the condenser it will pass in a substantially pure state from the chamber 20 through the pipe 33. The valve 35 is then partially opened and to an extent suflicient to regulate the flow of helium into the manitold 34 and thence to storage. When this point is reached the apparatus is in normal operation andthe gases beingthrottled through the valve 23 into the receiver 21 will carry in solution approximately 3% by volume of helium. All of this helium with the exception of probably ,th% to ths% will be 'ven ofl from the liquid in the receiver 21 an pass out through the pipe 24 as the liquid is being continuously drawn from the receiver 21, through valve 30 and pipe 29, into the chamber 18 of the condenser 19. These liquefied gases will then surround the chamber 20 and coil 17, forming the necessary refrigeration for liquefying all of the li uefiable constitucuts of the gases in said coil. Part of the liquid in the condenser chamber 18 will then be vaporized and the vaporized gas together with any excess liquid will pass through the pipe 31 into the chamber 37 of the heat inter changer giving up its refrigeration to the incoming gases.

It will be noted that there is no drop in pressure between the compressor and .the manifold 34 except such as is due to flow resistance; and that the pure helium is separated and stored for use by a single compressor and without either substantial drop in pressure or the necessity for any recompression.

For the purposes of this invention helium W9 is considered pure if it does not contain over 10% of other gases.

The apparatus is so controlled that the pot 20 may be kept immersed in liquid and the coil 17 may also be kept immersed in liquid, or a lower level of liquid may be maintained as desired. In any event the coil 17 and the pot 20 are kept at a temperature which is that produced by the boiling or evaporating of the non-helium constituents of the gas under. low pressure existent in the chamber 18. This temperature is sufiicient to liquefy substantially all of the non-helium constituents of the original gas in the coil 17 and pot 20, due to the fact that Within the coil and pot the pressure is very high. The gases produced in the chamber 18 pass through the pipe 31 to the chamber 37 of the heat interchanger, from which they pass out through the pipe 32.

It will, of course, be understood that the drawings show only a conventional representation of a heat interchanger and that the various pipes 25, 14 and 33 may be in the form,

of coils or zigzag passages in order to utilize.

to the maximum extent the low temperature of the outgoing gases to cool down the ingoing gasesin the pipe 14.

All of the helium in excess of 3% will pass,

out through th-epipe 33 in unliquefied form,': 00

of helium is only to The percentage of helium in the crude helium will vary with the pressure in the chamber 21.

My improved apparatus makes possible the separation of the helium in a commercially pure state in one step and the storage of the separated helium under the pressure of the compressor which supplies the crude gas. I

It will be noted that in this construction there is a continuous cyclic flow of crude helium fluid. The crude helium gas flows from the receiver 21, through pipes 24, 25 and 26, to the compressor, thence through pipes 12 and 14 and coil 17, to the pot 20. Here the gaseous impurities become liquefied and are delivered to the receiver 21 under lower pressure, and the crude helium escapes from the liquid as it is passed into the receiver.

The cycle involves two pressure phases, the higher pressure from the compressor to the valve 23, and the lower pressure from the valve 23 back to the compressor. Pure helium is continuously withdrawn from the cycle through pipe 33 and substantially heliumfree liquid is continuously withdrawn from the cycle through the pipe 29. Makeup fluid is admitted to the cycle through the pipe 10.

f the gas delivered through the pi e 10 contains less than 3% of helium, all 0 this n helium may be dissolved in the liquid in the pot 20 and pass through the receiver 21. The percentage of helium flowing out through the pipe 24 will be very much higher than that admitted through the pipe 10, so that the percentage of helium in the gas liquefied in the coil 17 will continuously increase until it exceeds 3%, and then the excess will remain as a free gas in the pot 20, and may fl-ow out through the pipe 33. Thus the apparatus may be operated until a concentration is arrived at where free helium may be drawn off, and the plant thereafter may be continuously operated under substantially uniform conditions. The amount of helium flowing out through the pipe 33 will equal the amount in the crude mixture delivered in through the i e 10. p f the mixture to betreated contains a comparatively high percentage" of helium, for example 3% or more, there may be separation in the pot 20 from the beginning of the operation when the temperature of li uefaction of the impurities has been reache Of course, if the percentage of helium in the gas treated id below the apparatus will not operate at the pressures stated, because of the solubility of that amount of helium in the liquid in the receiver 21.

The construction shown in Fig. 2 includes substantially all of the parts employed in the form shown in Fig. 1, but has in addition thereto a separate compressor for the crude helium and certain additional parts incidental thereto. The crude helium outlet pipe 26 instead of delivering directly to the compressor 11a delivers past the valve 27 to aseparate compressor 38 from which it is delivered through a pipe 39 and cooler 40, to a pipe 41, through 59 the interchanger to a coil 42 in the condenser The natural gas compressed by the compressor 11a and delivered through the pipe 12, cooler 13, pipes 14 and 16, to the coil 17, is not delivered directly to the pot or chamber 20. but isdelivered from the coil 17, through a pipe 43, past an expansion valve 44 The operation of this form of apparatus diifers from that shown in Fig. 1 in that the supply of natural gas is assumed to never have an amount of helium in excess of 3% and therefore all of the helium will be dissolved in the liquid produced by the lique- C3 faction of the other constituents in the coil 11,ae1,11e

21 w ere substantially all of the helium, to-

gether with the gases from the liquefied nonhelium constituents, passes as crude helium from the pipe 24 to the compressor 38. remainder of the liquefied non-helium constituents passes through the pipe 29 to the condenser as in the form shown in Fig. 1, while the recompressed crude helium delivered through the pipe 39 and cooler 40 is liquefied in the coil 42 and delivered to the pot or chamber 20. As this liquid contains a far higher percentage of helium than does that liquefied in the coil 17, substantially pure helium will separate from the liquid in the chamber 20 and pass out through the pipe 33 to the manifold 34, while the remainder of the liquid substantially free of helium will flow through the pipe 22 past the valve 23 into the chamber 21. All of the liquefied non-helium constituents are utilized in the The p condenser in substantially the same way as in the form shown in Fig. 1.

In Fi 3 there is shown an apparatus similar in a l respects to that shown in Fig. 2 so far as operation is concerned, but in which separate condensers are employed for the separate coils, and separate heat interchangers are employed for the incoming compressed natural gas and for the recompressed crude helium gas.

The condenser coil 17 is mounted in a condenser 19a and the liquefied gas containing the helium in solution is delivered past the valve 44 to the receiver 21. The gas supplid to the coil 17 is delivered through a pipe 16a in a heat interchanger 15a. The recompressed crude helium gas is delivered through the pipe 41 in a heat interchanger 15b, to the coil 42, and the pot 20, which are located in a separate'condenser 19b. The liquid from the bottom of the receiver 21 is delivered through the pipe 29, past the valve 30, to the condenser 196 where a ortion of the li uid is evaporated in efiecting the liquefactlon of the liquefiable constituents of the crude helium, while the cold gases and excess unevaporated liquid flow through the pipe 45, to the chamber of the condenser 19a. The crude helium separating in the receiver 21 passes through the pipe 24, to the chamber of the heat interchanger 15b, to the intake pipe 26 of the compressor 38.

Substantially pure helium which is not liquefied in the coil 42 passes from the pot 20. through the pipe 33 in the heat interchanger 15b, to the manifold or to any other receiver for the pure helium. The gas evaporating in the chamber of the condenser 19a passes through the pipe 31, to the heat interchanger 15a, and thence to the outlet pipe 32.

The pot 20 will receive the liquefied constituents of the crude helium and these may be withdrawn through the pipe 22 and valve 23. This pipe may deliver said liquid outside of the system or may deliver it to the receiver 21 as in Fig. 2, or may return it to the chamber of the condenser 19?). This liquid will be in comparatively small amount in respect to the amount of gas being delivered by the compressor 11a and will contain not to exceed about 3% of helium in solution. Thus the amount of helium withdrawn from the sysmm with such liquid will be comparatively small. If it is not desired to use this liquid for other purposes, its refrigerating value may be utilized in the system by returning it as above indicated.

In cases where the percentage of helium in the natural gas is comparatively low, my improved apparatus of the eneral type shown in Figs. 1, 2 and 3 may e usedwith a rectification column in place of the receiver 21.

In Fig. 4 I have shown such a modification of my invention. The apparatus here illustrated is similar in many respects to that shown in Fig. 2, so far as concerns the separate recompression of the crude helium, the liquefaction thereof, the separation of pure helium from the liquid, and the delivery of the residual liquid for further separation with the liquid produced by the compression and cooling of the natural gas. Instead of providing the receiver 21, I provide a rectification column 50 and mounted in the lower portion thereof is the coil 17 a which is connected to the pipe 14 leading through the heat interchanger, from the compressor 11a for the helium containing gas to be treated. The column is provided with the usual trays, baflles or the like 51, above the coil 17a, and the pipe 43a leading from the coil 17a, past the expansion valve 14a, delivers to the column 50 at a point intermediate of the height of the baflie plates 51. In the upper art of the column is some suitable form 0 reflux condenser 52, cooled by liquid withdrawn The residual liquefied crude helium collecting in the chamber 20 and from which the substantially pure helium has been Withdrawn, is delivered through the pipe 22a and expansion valve 23a to the upper end of the rectification column below the reflux condenser-52 and above the inlet from the pipe 43a. The crude helium gas which is not condensed in the reflux condenser 52 is delivered through a pipe 24a to the pipe 25 in the heat i'nterchanger'and back to the compressor 38 through the pipe 26.

The excess liquid delivered to the chamber around the reflux condenser 52 from the pipe 29a, together with any gas resulting from evaporation in this chamber, is delivered through the pipe 29?) to the chamber of the condenser 19 for liquefying the crude helium in the coil 42. The gas passes from this condenser, to the heat interchanger, through the pipe 31 in the same manner as in Fig. 2.

The pressure produced by each of the two compressors may be substantially 2000 pounds, while the pressure maintained in the chamber of the rectification column may be about 3 to 30 atmospheres.

It is thought that the operation will be clearly understood in view of the description of the operation of the other forms and the well known action'of a rectification column.

The, apparatus shown in Fig. 4 may be modified in various different details without departing from the spirit of'my invention. I have illustrated the rectification column, the crude helium condenser and the heat interchanger as three separate pieces of apparatus in Fig. 4, and have illustrated the heat interchanger and condenser as separate pieces of apparatus in the other figures. It will, of course, be obvious that in commercial practice these may be combined in the same housing and insulation and form a single unit.

The pipe 31, the top of the condenser 19 and the bottom of the heat interchanger 15 may be omitted, and the casing of the condenser and the casing of the heat interchanger may be connected. Also the pipe 296, the top of the rectification column and the bottom of the condenser 19 may be omitted.

The casing of the condenser and the casing of the rectification column may be directly connected so that the pot 20 and the tubes of the reflux condenser 52 will be in the same chamber and in superposed or in any other desired relative positions.

By means of my improved apparatus I am able to treat natural gas containing 1% or even less of helium and obtain a substantially pure product and at the same time obtain substantially all of the helium int-he original gas.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An apparatus for separating helium from gaseous mixtures, including a compressor for delivering the gaseous mixture at high pressure, means for cooling the gaseous mixture under said high pressure to eflect liquefaction of the non-helium constituents, means for delivering the separated pure helium, a receiver for the liquid constituents, means for delivering liquid constituents thereto under lower pressure, means for delivering to said compressor the crude helium separated from solution in said liquid, and means for delivering the residual liquid to effect said liquefaction in said cooling means.

2. An apparatus for separating helium from gaseous mixtures, including a compressor, a heat interchanger, a condenser having a collecting receiver therein, a second liquid receiver, means for delivering the gaseous I to said compressor.

mixture from said compressor through said heat interchanger to said collecting receiver, means for delivering liquid from said collectin receiver under lower pressure to said secon receiver, means for delivering pure helium from said collecting receiver through said heat interchanger, means for delivering liquid from said second'receiver to said condenser to cool the latter, and means for delivering crude helium from said second receiver through said heat interchanger back 3. An apparatus for separating helium from a gaseous mixture and puri y same, including means for delivering the gaseous mixture at high pressure, means for liquefying said mixture at said high pressure, a liquid receiver, a throttle for delivering liquid from said second mentioned means to said receiver at lower pressure and permitting the separation of crude helium from the liquid in said receiver, means for compressing the crude helium withdrawn from said receiver, means for liquefying the impurities from the recompressed crude helium, means for withdrawing the purified helium at the recompression pressure, and means for delivering liquid from said receiver in thermal contact with both of said liquefying means.

4. An apparatus for separating helium from a gaseous mixture and puri y helium, including a heat interchanger, a liquefier, a liquid receiver, a conduit for the compressed mixture extending through said interchanger and said liquefier to said receiver, a return conduit from said receiver vthrough said interchanger, a compressor connected to said last mentioned conduit and having a delivery conduit extending through said interchanger and said liquefier, a collectin receiver connected to said last mentione I conduit, a liquid withdrawal conduit from said collecting receiver to said first mentioned receiver, a helium withdrawal conduit from said collecting receiver through said interchanger, a conduit for delivering liquid from said first mentioned receiver to sa1d liquefier in thermal contact with said collecting receiver and the separate liquefying conduits for the gaseous mixture and the recompressed crude helium, and a conduit for delivering gases resulting from evaporation of said last mentioned liquid, to said interchanger.

5. An apparatus for separating helium 'from gaseous constituents, including a heat interchanger, a crude helium condenser, a

rectifying column having a liquefying coil, baflie plates and a condenser above the bafile plates, means for delivering the gas through said heat interchanger to said coil and thence to a point intermediate of the bafiie plates, means for delivering liquid from the bottom of said column to cool said second mening the ing the r tioned condenser, means for delivering liquid from said. second mentioned condenser to said crude helium condenser, means for re it to sa1d coil, means for delivering liquid from saidv coil to said baflle plates, means for delivering li uid from the base of said column to sa1d c amber, means for delivering liquid from said chamber to said crude helium rectifier means for withdrawing gas from said condenser tubes, means for compressing said gas, means for delivering said for compressing said mixture and delivering gas to said liquid receiving pot, means for withdrawing pure helium from said pot, and

means for deliverin liquid from said pot Itoo said rectifying co umn below said cham- 7. An apparatus for separating helium from a gaseous mixture, including means for liquefying said gaseous mixture a rectifying column, means for delivering the liquefied mixture to said column for the separation of crude helium gas therefrom, means for withdrawing said crude helium gas from the upper part of said column, means for compressing it, means for liquefying the nonhelium constituents of said compressed crude helium, and means for deliverin said liquefied constituents to said rectifying column.

8. An apparatus for separating helium from a gaseous mixture, including a rectifying column, means for liquefying said gaseous mixture and delivering it to said column for the separation of crude helium gas therefrom, means for withdrawing said crude helium gas from the upper part of said column, means for compressing it, means for cooling the compressed crude helium to a temperature resulting in liquefaction of substantially all of the non-helium constituents, and by the means of liquid withdrawn from the bottom of the rectifying column, and means for delivering said liquid non-helium constituents to the upper portion of the column.

9. An apparatus for separating helium from gaseous mixtures, including a .condenser chamber, a condenser coil and a liquid receiving pot bothdisposed in said chamber, the outlet of the coil being connected to said pot, means for delivering crude helium gas under pressure to said coil for the liquefaction of the non-helium constituents, a conduit for withdrawing pure helium from said receiving pot, a separating chamber, valve controlled means for delivering liquid from said pot to said separating chamber, a helium outlet at the upper part of said separating chamber, and valve controlled means for delivering liquid. from the bottom of said ieparating chamber to said condenser cham- 10. An apparatus for separating helium from gaseous mixtures, including a condenser chamber, a condenser coil and a li uid receiving pot both disposed in said cham er, the outlet of the coil being connected to said pot, means for delivering crude helium gas under pressure to said coil for the liquefaction of the non-helium constituents, a conduit for withdrawing pure helium from said receiving pot, a separating chamber, means for delivering liquefied constituents of said gaseous mixture to said chamber, a crude helium outlet conduit from the upper part of said separating chamber, and means for delivering liquid from the lower part of said chamber to said condenser chamber.

11. An apparatus for separating helium from gaseous mixtures, including a con denser chamber having a condenser coil and a receiving pot both disposed therein, said pot being connected to the outlet of said coil, means for delivering compressed crude helium gas under pressure to said condenser coil whereby the non-helium constituents are collected in liquid form in said pot, an outlet from said pot for the delivery of substantially pure helium separating from the liquid in said pot and under high pressure, a separating chamber, means for delivering liquid from said pot to said chamber, means for delivering non-helium constituents from said separating chamber, to said condenser chamber to cool said coil and said pot, and means for returning crude helium gas from said separating chamber for recompression.

Signed at Louisville, in the county of J efferson and State of Kentucky, this 16th'day of June, 1931.

. R. R. BOTTOMS. 

